Pettigrew Emma, Hickson Rebecca, Morris Steve, Kenyon Paul, Corner-Thomas Rene, Haslin Emmanuelle, Blair Hugh
School of Agriculture and Environment, Massey University, Palmerston North 4412, New Zealand.
Animals (Basel). 2021 Mar 10;11(3):770. doi: 10.3390/ani11030770.
Currently, 30-43% of New Zealand sheep farmers breed their ewe lambs, but few retain the offspring as replacements for their flock. No difference in lamb production as a yearling among singletons and twins born to ewe lambs and twins born to mature ewes has been reported, provided the ewe lambs had reached the 60-65% of their likely mature weight prior to breeding at seven to eight months of age. The aim of this experiment was to determine the lamb production from singletons and twins born to ewe lambs and twins born to mature ewes during their first two years of lambing. The experiment included 8-month-old ewes born as twins to mature ewes (M2, = 135), singletons born to ewe lambs (L1, = 135), and twins born to ewe lambs (L2, = 88), bred during the same period to the same rams, over two years. The efficiency of lamb production (total litter weight at weaning divided by the pre-breeding weight of the ewe, for all ewes presented for breeding) after two years of production was not significantly different ( > 0.05) among the groups (0.40 ± 0.02, 0.39 ± 0.02, and 0.39 ± 0.03, for M2, L1, and L2, respectively).
目前，30%至43%的新西兰绵羊养殖户会让他们的小母羊繁殖，但很少有人留下后代作为羊群的补充。据报道，小母羊所生的单胎和双胎以及成年母羊所生的双胎，在一岁时的产羔量没有差异，前提是小母羊在7至8个月大繁殖前已达到其可能成熟体重的60%至65%。本实验的目的是确定小母羊所生的单胎和双胎以及成年母羊所生的双胎在产羔的头两年的产羔量。该实验包括作为成年母羊双胞胎出生的8个月大的母羊（M2，n = 135）、小母羊所生的单胎（L1，n = 135）和小母羊所生的双胎（L2，n = 88），在两年内同期与相同的公羊配种。两年生产后的产羔效率（断奶时的总窝重除以参与繁殖的所有母羊繁殖前的体重）在各组之间没有显著差异（P>0.05）（M2、L1和L2分别为0.40±0.02、0.39±0.02和0.39±0.03）。
